Absorbing composition for tobacco smoke



United States Patent Ofifice 3,127,901 Patented Apr. 7, 1964 3,127,901 ABSORBING COMPOSITION FGR TOBACCO SMOKE Harry Whitefield and Mario Porta, both of 20 trada Val S. Martino, Turin, Italy N Drawing. Filed Apr. 14, 1961, Ser. No. 102,916

Claims priority, application Italy July 22, 1960 6 Claims. (Cl. 131-408) This invention relates to filters for absorbing noxious tobacco combustion products, said filters being either incorporated in cigarettes or separately suplied as an interchangeable cartridge in a suitable cigarette holder.

The instant absorbent is of decidedly improved efficiency over preparations known heretofore.

The absorbent comprises an alkyl-amine or a hydroxy alkyl-amine of a boiling point not lower than 60 C., preferably not lower than 90 C., a double salt of said amine with an inorganic salt (chloride, sulphate, alum) of a metal of the iron group, such as manganese, chromium, nickel or iron and a hydroxide of said metal in a colloidal state dispersed in the amine. Said components are thoroughly intermixed, the composition being employed in practice in a liquid carrier preferably selected from the group consisting of methyl alcohol, ethyl alcohol, sulphuric ether, methyl acetate and ethyl acetate. However other alcohols, ethers and esters can be employed by way of substitutes. After the composition has been applied to a filter cartridge, cigarette tip or other ultimate support, the carrier is evaporated.

The amines according to this invention can be normally in a liquid or solid condition. Aromatic and heterocyclic, amines, colored amines or odorous amines or amines generally of organoleptic characters which make them unsuitable for the purposes of this invention shall not be used. Among monoamines, amyl amines, pentyl amines, hexyl. amines, methyl-diethylamine and the series ranging between octylamines and heptadecylamines, whether of a saturated, primary or secondary type are more particularly suitable. Among diamines, propylene diamines, diamino pentanes, hexamethylendiamine, diamino-heptanes, -octanes, -nonanes and -decanes can usefully be employed. Among hydroxy alkyl-amines, especially Water-soluble amines, such as ethanolamine, methylethanolamine, ethylethanolamine, heptylethanolamine, isopropylamines, isobutylamines and isoarnylamines can be usefully employed. Among the four abovementioned ethanolamines, also diamines and triamines can usefully be employed.

The proportions of the three components in the improved composition considerably aifect efiiciency of the composition. It was first of all found that the free amine should sharply exceed in weight the sum of the weights of the double salt and colloidal hydroxide.

Optimum results were obtained with the following compositions:

Percent by Weight Free amine 80 to 93 Double salt 4 to 12 Colloidal hydroxide 3 to 9 The composition is hygroscopic in that it easily absorbs moisture from its environment. This circumstance is of basic importance for two reasons. Firstly, the absorbed moisture keeps the metal hydroxide colloidally dispersed in the amine, which is essential for the composition to fully develop its absorbing properties when incorporated by a cigarette tip or the like. Secondly, this moisture absorption should be taken care of in practice when the composition is employed for impregnating filters incorporated by cigarettes; generally, when the filter contains over about 20% composition, the absorbed moisture travels to the paper and tobacco and objectionably affects draught through the filter tip. Consequently, the proportion of composition retained by the filter should by no means exceed about 18-20%. On the other hand, this proportion is largely sufficient for practical purposes for, as was experimentally ascertained, proportions of about 1% already exhibit a certain activity, while proportions between about 10% and 15% are sufficient for practical purposes.

Though, as might appear at first sight, the composition according to this invention seems to be simply a mixture of the various ingredients, which can be prepared by intermixing the amine, double salt and colloidal hydroxide, this was not found to be true. More particularly, the composition successfully acts to purify and absorb only when the double salt and colloidal hydroxide are generated in situ through suitable chemical reactions. Therefore, one feature of this invention resides in the method of preparing the absorbing composition described above, comprising reacting at elevated temperatures said inorganic salt with excess amine in the presence of water to form said double salt, interrupting the reaction by adding a substantial volume of the liquid carrier (alcohol, ether, ester), continuing heating of the reagents long enough to form the metal hydroxide, and removing the aqueous phase. The remaining phase containing the amine, double salt and colloidal metal hydroxide in said carrier, is employed for impregnating a given support of a porous character adapted to act as a filter. The nature of the support does not appear critical, so that all materials known for the purpose can be employed at will, such as cellulosic materials generally, compressed vegetable, mineral or synthetic fibres which may be scoured or otherwise pretreated to enhance their absorbing power, natural or synthetic sponges, various conglomerates etc. For instance, a filter paper web can be passed through a bath comprising the instant composition diluted with methyl alcohol, whereupon the excess alcohol is evaporated in vacuum leaving the web ready for preparing filters therefrom. Impregnation can be effected by means of a concentrated bath, or repeated several times till the desired composition content has been absorbed by the support.

Example 1 100 grams of a mixture by equal parts of methylbutyl amine, isoamylamine or vinylamine are heated at about 100 C. with a solution of 12.5 grams ferric-chloride in 12.5 grams water in a closed container equipped with a reflux cooler. After half-an-hour 900 grams ethyl alcohol are added, heating being continued halfan-hour longer. The mixture is cooled, poured into a separating funnel, the aqueous phase being decanted from the alcoholic phase.

The analysis shows grams starting amines, 4 grams double sulphate of iron and the amine and 3 grams colloidal ferric-hydroxide. The alcoholic phase is utilised for impregnating a porous support as described above, alcohol being subsequently recovered in vacuum.

Example 2 grams triethanolamine (containing about 20% monoand di-ethanolamine) is heated at about 100 C. during one hour with 25 grams ferric-ammonium alum in a container equipped with a reflux cooler. The mixture is diluted with 900 grams ethyl alcohol and further heated during half-an-hour, thereupon cooled, the aqueous phase being decanted; the alcoholic phase contains 82 grams starting amines, 6 grams double sulphate of iron and the amine and 5 grams colloidal ferric-hydroxide.

Example 3 Equal parts of glycerodiamine and hexamethylendiamine are heated at about 100 C. with a concentrated ferrous-sulphate solution by a ratio by weight of 20% ferrous salt to 80% amines. After about 3 hours 900 grams sulphuric ether are added, heating being continued during a further hour. Finally, the temperature is lowered beneath C., the mixture is filtered and the filtrate is conveyed over a dehydrating substance in order to absorb the water residues. The ethereal phase is found to contain 67 grams starting amines, grams double sulphate of iron and the amine and 3 grams colloidal ferric hydroxide.

It should be understood that the invention is not limited to the abovementioned specific examples, numerous modifications being possible Within the scope of the appended claims.

What We claim is:

1. Absorbent composition for noxious tobacco-combustion products comprising an amine selected from the group consisting of alkyl-amines and hydroxyalkylamines of a boiling point of a least 60 C., a double salt of said amine and iron selected from the group consisting of sulfates and chlorides, and ferric-hydroxide colloidally dispersed in the amine.

2. Absorbent composition for noxious tobacco-combustion products comprising 80 to 93% by weight of an amine selected from the group consisting of alkyl-amines and hydroxyalkyl-amines of a boiling point of at least 60 C., 4 to 12% of a double salt of said amine and iron selected from the group consisting of sulfates and chlorides, and 3 to 9% of ferric-hydroxide colloidally dispersed in the amine.

3. A cigarette tip incorporating a filtering material comprising a porous support having deposited thereon at least 1% by weight of an absorbent composition for noxious combustion products of tobacco, said composition comprising an amine selected from the group consisting of alkylamines and hydroxyalkyl-amines having a boiling point of at least 60 C., a double salt of said amine and iron selected from the group consisting of sulfates and chlorides, and ferric-hydroxide colloidally dispersed in the amine.

4. A cigarette tip incorporating a filtering material comprising a porous support having deposited thereon at least 1% by Weight of an absorbent composition for noxious combustion products of tobacco, said composition comprising 80 to 93% of an amine selected from the group consisting of alkyl-amines and hydroxyalkyl-amines having a boiling point of at least 60 C., 4 to 12% of a double sulfate of said amine and iron, and 3 to 9% of ferric-hydroxide colloidally dispersed in the amine.

5. A method of preparing an absorbent composition for noxious combustion products of tobacco comprising heating an inorganic iron salt selected from the group consisting of sulfates, chlorides and ferri-ammonium sulfate in the presence of Water, with an excess of an amine selected from the group consisting of alkylamines and hydroxyalkyl-amines having a boiling point of at least C. until part of said salt is reacted with the amine forming a double salt of said amine and iron corresponding to the inorganic iron salt; then adding to the reaction mass a substantial volume of a liquid carrier selected from the group consisting of methyl alcohol, ethyl alcohol, sulfuric ether, methyl acetate and ethyl acetate, in order to interrupt the formation of said double salt; heating the reaction mass and the added carrier to form colloidal ferric-hydroxide in the mass, and evaporating the carrier.

6. A method of preparing an absorbent composition for noxious combustion products of tobacco comprising heating ferri-ammonium alum in an excess of an amine selected from the group consisting of alkyl-amines and hydroxyalkyl-amines having a boiling point of at least 60 C. until part of said alum is reacted with the amine forming a double sulfate of said amine and iron; then adding to the reaction mass a substantial volume of a liquid carrier selected from the group consisting of methyl alcohol, ethyl alcohol, sulfuric ether, methyl acetate and ethyl acetate, in order to interrupt the formation of said double salt; heating the reaction mass and the added carrier to form colloidal ferric-hydroxide in the mass, and evaporating the carrier.

References Cited in the file of this patent UNITED STATES PATENTS 757,514 Thoms Apr. 19, 1904 1,859,379 Chesley May 24, 1932 2,815,760 Schreus et al Dec. 10, 1957 2,832,351 Hale Apr. 29, 1958 2,881,772 Touey et al Apr. 14, 1959 2,968,306 Touey et al. Jan. 17, 1961 OTHER REFERENCES Volumi Polmonari In Fumatori Soni Broncopatici Prime E Dopo Uso di Filtro Chimico per Sigarette, Pub. in vol. 55, No. 39 (May 16, 1962), of Minerva Medica, pages 1-16. 

3. A CIGARETTE TIP INCORPORATING A FILTERING MATERIAL COMPRISING A POROUS SUPPORT HAVING DEPOSITED THEREON AT LEAST 1% BY WEIGHT OF AN ABSORBENT COMPOSITION FOR NOXIOUS COMBUSTION PRODUCTS OF TOBACCO, SAID COMPOSITION COMPRISING AN AMINE SELECTED FROM THE GROUP CONSISTING OF ALKYLAMINES AND HYDROXYALKYL-AMINES HAVING A BOILING POINT OF AT LEAST 60*C., A DOUBLE SALT OF SAID AMINE AND IRON SELECTED FROM THE GROUP CONSISTING OF SULFATES AND CHLORIDES, AND FERRIC-HYDROXIDE COLLOIDALLY DISPERSED IN THE AMINE. 